Hooking a series of empties along a curve
There is a workaround to emulate dupliframe.

Add a curve.

Add a plane. In edit mode scale it way down. 

Add an "Array" modifier to the plane, set the length to 'fit curve' and select the curve. Deselect "Relative offset" and select "Constant offset", set the value to the spacing you want between each empty.

Add a curve modifier and set it to the curve.



Create an empty object. In object mode, select it then select the arrayed plane (not the curve). Go to Object > Parent (or press  CTRL  + P) and select "Object".

Select the arrayed plane and go to object info > Instancing and select "Faces". Uncheck "Render instancer" so that the plane doesn't get rendered. (Useless in your case since you are only interested in exporting it)



Now when you export your file, for example in fbx, it will contain the individual empties. Just delete the "plane" object to get rid of it. No need to apply the modifiers.



If you want for example your empties to be 2 meters above the curve, just move the original empty 2 meters along the z axis in object mode.